Creating scheduled disk snapshots

You can configure automatic disk snapshot creation based on a schedule.

In the schedule, you specify:

• Disks for which the snapshots will be created. One schedule can include multiple disks, and one disk can be added to multiple schedules.
• Frequency of snapshot creation by hour, day, week, or cron expression. The time is provided for the UTC time zone.
• Snapshot retention settings.
• Scheduled snapshot description and labels (you can only use the API to add them to the schedule settings).

Snapshots are created in the same folder as the schedule, even if the schedule has disks from other folders.

A single snapshot can only be created for one disk at a time. All other schedules for the disk in question are ignored until a snapshot for this disk is created.

You can create snapshots of network drives, such as HDDs, SSDs, and non-replicated SSDs, as well as ultra-high performance network storages with three replicas (SSD).

For non-replicated SSDs and ultra-high performance network storages with three replicas (SSD), the snapshot time is not determined.

To take snapshots of local disks residing on dedicated hosts, use Yandex Cloud Backup. This service supports Ubuntu, CentOS, CentOS Stream, and Windows Server.

A quota, which can be increased, applies to the number of schedules per cloud. Fixed limits apply to the number of disks in a schedule and the number of schedules for a disk.

Schedules can be used free of charge. You only pay for storing the snapshots. For more information, see Compute Cloud pricing policy.

Cron expressionsCron expressions

You can specify a snapshot schedule using cron expressions, which include five fields: Minutes Hours Day-of-month Month Day-of-week. You can also use special expressions, e.g., to create snapshots every hour or every day.

Possible field valuesPossible field values

Field name	Acceptable values	Supported special characters
Minutes	0-59	,, -, *, /
Hours	0-23 (UTC)	,, -, *, /
Day of month	1-31	,, -, *, ?, /
Month	1-12, JAN-DEC	,, -, *, /
Day of week	1-7, MON-SUN	,, -, *, ?, /

Special charactersSpecial characters

You can use the following special characters in cron expressions:

• *: Select all values in the field.

  * character in the Hours field: Snapshots are created every hour.

• ?: Select any field value. You cannot specify Day of month and Day of week at the same time. If you entered a value or * in one of these fields, enter ?. in the other.

  10 in Day of month and ? in Day of week: Snapshots are created every tenth day of the month.

• -: Select a range of values.

  The 10-12 range in Hours: Snapshots are created at 10 a.m., 11 a.m., and 12 p.m.

• ,: Select multiple values.

  MON, WED, FRI in the Day of week field: Snapshots are created on Monday, Wednesday, and Friday.

• /: Increment the value.

  2/6 in Hours: Snapshots are created at 2 a.m., 8 a.m., 2 p.m., and 8 p.m.

Examples of cron expressionsExamples of cron expressions

Cron expression	Description
0 * ? * *	Snapshots are created at the start of every hour.
15 10 ? * *	Snapshots are created every day at 10:15 a.m.
0 9,18 ? * 1-5	Snapshots are created every weekday at 9 a.m. and 9 p.m.

Special expressionsSpecial expressions

Cron expression	Description	The same as
@hourly	Snapshots are created at the start of every hour.	0 * ? * *
@daily @midnight	Snapshots are created every day at midnight.	0 0 ? * *
@weekly	Snapshots are created every Sunday at midnight.	0 0 * * SUN
@monthly	Snapshots are created every first day of the month at midnight.	0 0 1 * *
@yearly @annually	Snapshots are created every year on January 1 at midnight.	0 0 1 1 *

Storing snapshotsStoring snapshots

With schedules, you can set and configure a snapshot retention policy. For each disk included in a schedule, you can store:

• All created scheduled snapshots.
• Only the last few snapshots. The oldest snapshots created on schedule are automatically deleted once the specified number is exceeded. For example, if you want to keep only the last five snapshots, the first snapshot is deleted after the sixth one is created, the second is deleted after the seventh one is created, etc.
• Only the snapshots younger than a certain age, e.g., those created for the last few days. The oldest snapshots created on schedule are automatically deleted once the specified age is reached.

The retention policy applies to all disks in a schedule.

Snapshots are deleted only while the schedule is at the ACTIVE status.

Snapshot namesSnapshot names

For a scheduled snapshot, a name up to 63 characters long is generated. The name consists of the following items separated with underscores:

• Name of a virtual machine the disk is attached to (up to 24 characters), or the unattached line, if the disk is not attached to any VM.
• Disk name (up 20 characters).
• Snapshot creation date and time (UTC) in YYYYMMDDhhmm format (year, month, day, hour, and minute).
• Line consisting of four random alphanumeric characters.

For example, if the test-disk-with-a-long-name disk is attached to the test-vm VM, its scheduled snapshot created on September 1, 2022 at 03:30 p.m. UTC will have the following name:

test-vm_test-disk-with-a-lon_202209011530_pd2k

Schedule statusesSchedule statuses

• CREATING: Schedule is being created.
• ACTIVE: Schedule is on: based on it, new disk snapshots are created and old ones are deleted (if the respective parameter has been specified in snapshot retention).
• UPDATING: Changes are being made to the schedule settings or the list of attached disks.
• INACTIVE: Schedule has been paused, snapshots are not created or deleted.
• DELETING: Schedule is being deleted.

All snapshot creation or deletion operations that started prior to changing, pausing, or deleting the schedule will be completed.

See alsoSee also

• Guides on disk snapshots and schedules